1. Field of the Industrial Application
The present invention relates to a gas insulated switchgear of a double bus system including a bus sectioning use and a bus tieing use gas insulated switchgear unit which are used such as in a double bus four bus tie system.
2. Conventional Art
In order to decrease the size of the gas insulated switchgear and to shorten the bus length a variety of ideas have been also proposed for the arrangement of a bus potential transformer (hereinbelow abbreviated as bus PT) and a bus work earthing switch (hereinbelow abbreviated as bus ES). Among these ideas is a gas insulated switchgear in which bus PT and bus ES dedicated units are disposed separate from a switchgear unit. Also, a gas insulated switchgear is provided such that bus PTs and bus ESs for all of the main buses are collectively disposed in a bus sectioning gas insulated switchgear unit. Further, JP-B-61-27966(1986) discloses an example of conventional gas insulated switchgears.
In order to meet a primary requirement of connection between two main buses via a switching device with a minimum distance as well as to meet a newly added requirement to additionally dispose a bus PT and a bus ES, the arrangement of the bus sectioning and the bus tieing gas insulated switchgear unit in the above explained conventional countermeasure results in the expansion, by stacking multiples of the units. As a result, problems such as the elongation of the bus, enlargement of installation area and poor earthquake resistance are caused.